The present invention relates to gut of the type stretched on rackets for use in tennis, badminton, squash, and the like, and to methods for making a gut.
Generally, materials for this sort of gut have been conventionally classified into synthetic resins such as polyamide, etc. and natural materials such as intestines of sheep, whale tissue, etc. In use, the gut, either synthetic or natural, is stretched on a racket. Longitudinal lines are first formed, and then lateral lines are formed at a large tension, so that friction between the longitudinal lines and the lateral ones may readily cause damage to the gut.
One approach in an effort to reduce or eliminate such damage has been to apply paraffin and/or silicone oil to the gut at the time of stretching on the racket. In another approach one of the above-described oils or polyolefin, silicone or nylon, or a wax emulsion is applied to the gut at the time of manufacture of the gut. The purpose of such materials is to prevent damage to the gut at the time of stretching of the gut on rackets and prevent wear of the gut due to frictional heat produced between longitudinal strings and lateral ones during play of each game.
While these additives have been of some initial aid, the effect is soon lessened due to shock at the time of hitting of balls or sticking of sand, dust, and the like to the gut.
Accordingly, an essential object of the present invention is to provide an improved gut which prevents, for a long period of time, damage to the gut at the time of stretching of the gut on a racket and wear of the gut at the time of hitting of balls.
It is known that ethylene tetrafluoride resin is excellent in resistance to static friction and dynamic friction. However, it has not been known how to take advantage of this characteristic in connection with gut for rackets. It is another object of the invention to provide a new gut with ethylene tetrafluoride resin and a method of producing same.